A 10L helium balloon at a pressure of two bar at 27C. Some O2 is now inside in balloon and final volume is made 30L. the pressure also fell to 1 bar at similar temperature. the partial pressure of O2 at end is?Solution) For helium.
n(He)=P(1)V(1)/RT.for oxygen n(O)=P(2)V(2)/RTpartial pressure of O2= (mole fraction of O2).(Total pressure)
= [ P(2).V(2) / P(2).V(2) + P(1).V(1) ].(1)= 1.30 / 1.30 + 2.10=30/30+20=3/5 barHence 0.6 bar (ANS)